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Huntron Access USB
Huntron Access 2 USB
USER'S MANUAL
P/N 21-1352
Rev. P
Version 1.1
November, 2021
Copyright  2018 Huntron, Inc. All rights reserved.
Huntron, Tracker, ProTrack, and Huntron Access are registered trademarks of Huntron, Inc. All
other names are trademarks or registered trademarks of their respective companies.
This document may not be copied in whole or in part, or otherwise reproduced except as specifically
permitted under U.S. copyright law, without the prior written consent of Huntron, Inc.,
15720 Main Street, Suite#100, Mill Creek, WA, 98012, USA.
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Summary of Contents for Huntron Access USB

  • Page 1 November, 2021 Copyright  2018 Huntron, Inc. All rights reserved. Huntron, Tracker, ProTrack, and Huntron Access are registered trademarks of Huntron, Inc. All other names are trademarks or registered trademarks of their respective companies. This document may not be copied in whole or in part, or otherwise reproduced except as specifically permitted under U.S.
  • Page 2 (1) year from the date of purchase. Huntron further warrants that the software will perform in substantial conformance with the system specifications of the Huntron Access at the time of purchase and for the period of one (1) year thereafter.
  • Page 3: Table Of Contents

    Hardware Features of the Huntron Access ..............8 Software applications for the Huntron Access ............. 9 Specifications ...................... 10 Specifications of Huntron Access USB Models ............10 Specifications of Huntron Access 2 USB Models ............12 Specifications of NFSA Probe ..................13 Safety Information (Information sur la sécurité) ..........
  • Page 4 Mounting the NFSA Probe (Access 2 NFSA Only) ..........24 Connecting a Huntron Tracker to the Huntron Access ........25 Connecting the Huntron Access to a PC ............. 26 SECTION 4 HARDWARE MAINTENANCE ................27 Rail Lubrication ....................27 Procedure ........................27 Calibration Requirements ...................
  • Page 5 Inductors ......................53 Inductor Analog Signature ..................53 Signatures of Inductors in 50, 10V and 2KHz ............53 Affect of Frequency (F ) on Inductor Signatures ............54 Affect of Voltage (V ) on Inductor Signatures............. 54 Affect of Internal Resistance (R ) on Inductor Signatures ..........
  • Page 6 Signatures of a Digital IC ..................... 82 Signatures of Logic IC Families ..................83 Comparing Two TTL Families ..................84 CMOS Logic Family ...................... 85 CMOS Components and Test Frequency (F ) .............. 86 Troubleshooting Digital Logic ICs ................86 Review .........................
  • Page 7: Section 1 Introduction

    Z-axis. The Huntron Access basically consists of three axes which move a test probe along an XY plane. Once the probe reaches an XY coordinate, an up or down Z movement can be initiated so that the test probe makes contact with a test point on the target printed circuit board.
  • Page 8: Features

    • Connection to any external tester is via two BNC connectors mounted at the back of the Huntron Access. The Probe BNC connector is for the Signal from the external tester, and the Common BNC is for the ground of the external tester.
  • Page 9: Software Applications For The Huntron Access

    • There are 5 Common connectors accessible at the front panel which allows connection to the printed circuit assembly signal reference points. • Huntron Access USB with Tracker and the Huntron Access 2 USB with Tracker have a built in Access Tracker (Model 30) that creates a complete test system.
  • Page 10: Specifications

    Specifications Specifications of Huntron Access USB Models Specification Huntron Access USB Comments Huntron Access USB w/Tracker 26.5” W, 24.5” D, 13” H Physical Dimensions 67.31 cm W, 62.3 cm D, 33.02 cm H 19.4” W by 14” D Max. board-under-test Max thickness is 0.1”...
  • Page 11 70.5 oz. max. Without NFSA Probe Web cam Not on Access NFSA Tracker specifications See Access Tracker Specifications (Access USB w/Tracker only) Safety considerations Front panel STOP switch for stopping CE mark and ETL listed motors User’s Manual 21-1352 Rev P...
  • Page 12: Specifications Of Huntron Access 2 Usb Models

    Specifications of Huntron Access 2 USB Models Specification Huntron Access 2 USB Huntron Comments Access 2 USB with Tracker Huntron Access 2 NFSA Huntron Access 2 NFSA Ready 36” W, 29” D, 15.7” H Physical Dimensions (91.44 cm W, 73.66 cm D, 39.88 cm H) 22”...
  • Page 13: Specifications Of Nfsa Probe

    Storage temperature -58 degrees F to 140 degrees F (-50 degrees C to +60 degrees C ) Operating Humidity 45 to 70% R.H. Storage Humidity 0 to 70% R.H. Indoor Use Only Operating Altitude 6,560ft (2,000m) Storage Altitude 32,800ft (10,000m) Mains Supply Voltage Up To +/-10% of the Nominal fluctuations...
  • Page 14 Specifications for Access Tracker Electrical Specifications subject to change without notice Open Circuit Voltage (Vs): 24 selections of peak voltage: 200mV, 400mV, 600mV, 800mV, 1V to 20V in 1V steps including 10V (Low), 15V (Med 1), 20V (Med 2) Source Resistance (Rs): 10Ω, 20Ω, 50Ω, 100Ω, 200Ω, 500Ω, 1kΩ, 16 selections of resistance: 2kΩ, 5kΩ, 10kΩ, 20kΩ, 50kΩ, 100kΩ,...
  • Page 15: Safety Information (Information Sur La Sécurité)

    Safety Information (Information sur la sécurité) Symbols and Warnings: (Symboles et avertissements) The following symbols are used either in this manual or on the unit: Les symboles suivants sont utilisés soit dans ce manuel ou sur l'appareil: Protective Ground (Earth) Terminal: Do not disconnect any protective ground wires. Rez de protection (terre): Ne débranchez pas les fils de terre de protection.
  • Page 16 étaient l'axe Z et l'axe X sont à placer aux limites avant / arrière et droite / gauche. L'utilisateur ne devrait pas avoir les doigts ou les mains près de ce point lorsque l'appareil est en mouvement. The all Huntron Access models conform to the following Standards: EN 55011 EN 61000-3-2:2000...
  • Page 17: Environment Conformity Quality

    Environment Conformity Quality For more information see our website www.huntron.com/corporate/environment.htm Environment Huntron is aware of the recycling needs for Waste Electronic and Electrical Equipment (WEEE) and is co-operating with systems established, worldwide for the collecting and recycling of our products.
  • Page 18: Conformity

    Conformity to Huntron Quality Standard at www.huntron.com/corporate/docs/conformity.pdf. Quality Huntron has been producing quality products and supporting customers all over the world for several decades. Our products conform to our Quality Manual. For information see our Quality Statement at www.huntron.com/corporate/docs/quality-statement.pdf. User’s Manual...
  • Page 19: Section 2 Theory Of Operation

    Introduction The purpose of this section is to simply explain the functional characteristics of the main components of the Huntron Access system. Functional Overview The Test probe on the Z axis is directly connected to the BNC Probe connector located on the side or back panel.
  • Page 20: Controls And Signal Connections

    Controls and Signal Connections Safety Stop Switch The safety stop switch is located on the right side of the Huntron Access. Depressing this stop switch will cause all motor movement in the X and Y directions to immediately stop and have their respective power turned off. If the Z axis was in the depressed position (down position), it will automatically move up to its home position, thus relieving any pressure that was put on the board-under-test.
  • Page 21: Common 3 Banana Jack

    This USB port is used to connect the Huntron Access to a PC. Probe BNC This BNC is connected to the probe tip of the Huntron Access. It is used to connect external instruments to the probe tip. It is also used to connect to Channel A BNC to use the internal Access Tracker (With Tracker Only).
  • Page 22: Not Used / Auxiliary (Aux) Connector (Access With Tracker Only)

    Not Used / Auxiliary (AUX) Connector (Access With Tracker Only) The Auxiliary (AUX) 9 pin DIN connector pins are shown below. These pins can be used for synchronizing and triggering the Access Tracker with other external Functional Test Instrumentation. Fig 9. Rear panel 9 pin Din connector pin outs. Pin 1: SINE.
  • Page 23: Section 3 Installation

    Huntron Access USB Probers. Installing the Hardware 1. Locate the unpacking sheet that was supplied with the Huntron Access. 2. Follow the unpacking steps as outlined in the unpacking sheet. 3. Make sure the Red stop blocks and Z Probe Locking Screw or Pin have been removed.
  • Page 24: Mounting The Nfsa Probe (Access 2 Nfsa Only)

    Mounting the NFSA Probe (Access 2 NFSA Only) 1. Manually move the Z Head of the Access to the front center. 2. Pull the Z Probe all the way down. 3. Remove the Probe wire from the Probe receptacle. 4. Remove the 3-48 3/8” screw (P/N 07-3208) and the 3-48 lock nut (P/N 07-3250) holding the Probe Block to the Z Rail.
  • Page 25: Connecting A Huntron Tracker To The Huntron Access

    PROBE BNC on the Huntron Access. Access with Tracker inside/Access 2 with Tracker inside: If using the built-in Access Tracker connect the Channel A BNC on the Huntron Access to the Probe BNC on the Huntron Access using the supplied 12” BNC cable.
  • Page 26: Connecting The Huntron Access To A Pc

    Connecting the Huntron Access to a PC Connect the USB cable to the USB port on the Huntron Access. Connect the other end of the USB cable to an available USB port on the computer. Follow the instructions for installing Huntron Workstation, support software and software drivers listed on the Getting Started document supplied with this system.
  • Page 27: Section 4 Hardware Maintenance

    The rails should be lubricated once a month. Warning: The linear raceways have to be lubricated using the supplied linear lube (Huntron Part Number 98-0116) which is included in your Tool kit. Do not use with any other lubricant. Procedure 1.
  • Page 28: Calibration Requirements

    There are no user calibration requirements. The unit is factory aligned and does not need calibration. Removing or loosening screws on the mechanical parts of the Access can affect movement accuracy. If the unit is not moving accurately, please call Huntron Technical Support for further instructions. User’s Manual 21-1352 Rev P...
  • Page 29: Color Camera Adjustments

    Color Camera Adjustments The camera lens on the color camera has a separate focus and aperture adjustment ring. These adjustment rings can be locked via a locking screw. The aperture setting is factory set and will be in the locked position. The setting is shown below. If the camera image appears dark even with maximum light intensity, it may be necessary to adjust the aperture.
  • Page 30: Spring Contact Probes

    Probe manual. Replacing the Probe Tip Use the needle nose pliers supplied with the Huntron Access tool kit to pull the probe out of the receptacle. It is not necessary to remove the probe holder to do this. Simply grip the probe tip with the pliers and pull straight downward.
  • Page 31: Probe Kit

    The rest of the broken tip will come out. Probe Kit A probe kit (P/N 98-0126) is supplied with the Huntron Access probers. The Access probers are shipped with a 4 Point Tapered Crown Probe installed. Refer to the datasheet included with the Prober Kit for detailed probe information.
  • Page 32: Mil Probe Holder

    50 Mil Probe Holder The 50 mil probe holder can be used to replace the 100 mil probe holder when probing fine pitch components. 1. Make sure the Access Prober is powered off. 2. Manually move the Z Head of the Access to the front center. 3.
  • Page 33: Probe Styles

    QA Technology part number: 050-PTP2514H (Huntron P/N 07-2196) Probe Receptacle Specifications The general specifications for the probe receptacle, which is press fitted into the Huntron Access probe holder, are as follows: The IDI part number of this receptacle is 100211-007 or R-50C-WW-025 (Huntron P/N 07-2197).
  • Page 34: Section 5 Support Accessories

    Board Spacer Board Spacer for Access USB p/n 98-0111 The part number for the board spacers for a Huntron Access 2 USB and Huntron Access 2 USB with Tracker is 98-0292. These spacers are longer and have 4 slots. User’s Manual...
  • Page 35: Crossbar

    The Crossbar is normally used to hold the front side of the test board. Cross Bar for Access USB P/N 98-0393 The part number for the longer Crossbar for a Huntron Access 2 USB and Huntron Access 2 USB with Tracker is 98-0119.
  • Page 36: Slide Bar

    Slide Bar The Slide Bar mounted on a Crossbar holds the left front corner of the Printed Circuit Assembly. The front of a Slide Bar on a Crossbar can hold the test board away from the Crossbar to allow components on the front edge of the board to be reached by the probe tip.
  • Page 37: Slide Bar Extension

    Slide Bar Extension The Slide Bar Extension mounted on a Crossbar can hold the unsupported side of the test board. The Slide Bar Extension can also be configured with a Slide Bar for additional support of the side of the test board. Slide Bar Extension P/N 98-0132 User’s Manual 21-1352 Rev P...
  • Page 38: Extended Slide Bar

    Huntron Access. In this case, use the Crossbar with two Slide Bar Extensions and two Extended Slide Bars. The Extended Slide Bar is no longer included with the Access Prober.
  • Page 39 When using Extended Slide Bars, the board must be mounted in the top slot of the Huntron Access. The Crossbars (which hold the Slide Bar Extensions and Extended Slide Bars) are then mounted in the middle slot. This figure shows how to mount either an irregularly shaped board or a long and narrow board.
  • Page 40 When using the Extended Slide Bar, the board must be mounted in the top slot of the Huntron Access. The additional Crossbar (which holds the Extended Slide Bar) is then mounted in the middle slot. User’s Manual 21-1352 Rev P...
  • Page 41: 5-6 Pca Support Kit

    Two blocks are included in the kit. The block can hold three different length pins which are used to prevent large boards from flexing. (PCA Support Kit is included with the Huntron Access 2 Models) The 3” pin is used for boards mounted in the top slot.
  • Page 42: Section 6 Testing Passive Components (With Tracker Only)

    Access Tracker's test range parameters: voltage, resistance and frequency. Put the red test lead in the Channel A jack and the black test lead in the Common jack. Micro Probe Adjustment Figure 6-1. Huntron MicroProbe Adjustment. User’s Manual 21-1352 Rev P...
  • Page 43 To display the analog signature of a resistor: 1. Select the Tracker tab of the Signature pane of the Huntron Workstation Software. 2. Select the 50 ohm range by clicking the Resistance dropdown button and selecting 3. Place or clip a test lead on the opposite ends of a resistor and observe the signature.
  • Page 44: The Affect Of R On Resistor Analog Signatures

    150  1.5 k 15 k 150 k Vs=10V, Rs=54 (Use 10V, 50, 200Hz) Figure 6-2. Signatures of Different Resistors in 4 Ranges. Now that you have an idea of what the signatures of different resistor values look like in different ranges, the next part will give you an idea of what happens when you vary R source resistance, V source voltage and F...
  • Page 45: The Affect Of F On Resistor Analog Signatures

    The Affect of F on Resistor Analog Signatures. Select the 10V, 50 and 20Hz range. Change the Frequency to 60Hz, 1KHz and 5KHz. Observe the resistor signatures in the following figures do not change as F changes. Fs = 20 Hz Fs = 60 Hz Fs = 1KHz Fs = 5KHz...
  • Page 46: Review

    Review • The signature of a purely resistive circuit is a straight line because the relationship between voltage and current in a purely resistive circuit is linear. • This straight line signature can vary from − completely horizontal (an open) −...
  • Page 47: Capacitors

    Capacitors With a capacitor connected to the Access Tracker, the test signal across it responds quite differently than a resistor. The typical analog signature of a capacitor is an elliptical or circular pattern due to the fact that relationship between the test signal's current and voltage are non linear.
  • Page 48: Signatures Of Capacitors

    1. Select the 10V, 50 and 60Hz range 2. Place or clip a test lead on the opposite ends of a capacitor and observe the signature. Signatures of Capacitors The figure below shows analog signatures for four different value capacitors, 1000 f, 100 f, 10 f and 1f.
  • Page 49: Affect Of Frequency

    ) on the Signature of a 0.1 F Capacitor Affect of Frequency (F Select 10V, 1K and 20Hz. Then select 60Hz, 500Hz and 5KHz. = 20 Hz = 60 Hz = 500 Hz = 5 kHz Figure 6-10. Signatures of A 0.1 F Capacitor at Different Frequencies. Note that as the test signal frequency increases, each signature changes from a horizontal elliptical pattern to a vertical elliptical pattern.
  • Page 50: Understanding Capacitor Analog Signatures

    Understanding Capacitor Analog Signatures Figure 6-13. Access Tracker Core Circuit Block Diagram with a Capacitor. The Huntron Workstation Software displays the Access Tracker signature as a response to its test signal, an analog signature that represents the relationship between voltage, current and resistance of a component.
  • Page 51: Capacitor Leakage Failures

    − V increases so current decreases proportionately − The elliptical signature becomes increasingly vertical Table 3-1 shows the Access Tracker's limits for the minimum and maximum capacitance values it can handle. = 20 Hz. = 5 kHz 0.01 F - 1 F 100 pF - 0.01 F 100 k...
  • Page 52: Review

    Normal Capacitor Leaky Capacitor Figure 6-16. Signatures of A 10 F Capacitor with Dielectric Leakage at 10V, 500, 60Hz Again, this example only simulates the leakage flaw by adding a 68  resistor in parallel to a 10 F capacitor. It shows the signature change from a normal circular ellipse pattern to a sloped and depressed vertical pattern.
  • Page 53: Inductors

    Inductors Inductors, like capacitors, have elliptical analog signatures and respond to Access Tracker's test signal non-linearly. Also like capacitors, an inductor's reactance (resistance to an AC test signal) is dependent on the test signal's frequency. Because of the way they are constructed using wire with some amount of resistance in it, it is hard to find a pure inductance.
  • Page 54: Affect Of Frequency (F ) On Inductor Signatures

    Affect of Frequency (F ) on Inductor Signatures Select 10V, 50, 60Hz. Then Select 1KHz and 5KHz. = 60 Hz = 1KHz = 5KHz Figure 6-18. Affect of Varying F on 12,000 µH Inductor Signatures. Note that the signature changes from a vertical position to a horizontal position as the frequency increases.
  • Page 55: Affect Of Internal Resistance

    Affect of Internal Resistance (R ) on Inductor Signatures Select 2V, 10, 60Hz. Then Select 50 and 200. = 10  = 50  = 200  Figure 6-20. Affect of Varying R on 12,000 µH Inductor Signatures. Note that the signature changes from a horizontal to a vertical position as the Access Tracker's internal resistance R increases.
  • Page 56 make the inductive characteristics different from those constructed without. The Access Tracker responds with a unique analog signature for each inductor type. = 20 Hz. = 5 kHz 100H – 1000H 50mH – 1000mH 100 k 10  1H – 100H 1uH –...
  • Page 57: Review

    Review • Inductors display elliptical signatures similar to capacitors. Since the inductor also exhibits resistance, due to its construction, the ellipse may be distorted. • As the Access Tracker test signal’s frequency is increased, the ellipse signature becomes flatter. This response is opposite to that of a capacitor. •...
  • Page 58 • Another simple test for a speaker or microphone is to apply the Access Tracker signal = 50 , F in V = 10 V, R = 60Hz range to the device input leads and listen for the 60 Hz tone or audible hum. •...
  • Page 59: Electromechanical Switching Components

    Electromechanical Switching Components Switches are electrical devices that either stop or allow current to flow in a circuit. They are either in an on or off state. Switching devices come in all types and sizes. There are simple mechanical switches, relays, optical switches, and many kinds of semiconductor switches.
  • Page 60: Electromechanical Relays

    • As the test signal's voltage decreases with each range change, the volts per division of the horizontal axis also decreases so that its analog signature becomes more pronounced. This is caused by the small voltage drop across the switch's internal resistance.
  • Page 61: Review

    Review • The Access Tracker can test switches in real time. This makes an excellent test for micro switches, power switches, control switches, pressure and heat sensor switches. • As the mechanical switch closes, watch for erratic or discontinuous signature. Switch bounce will display as multiple closure signatures.
  • Page 62: Section 7 Testing Discrete Semiconductors (With Tracker Only)

    SECTION 7 TESTING DISCRETE SEMICONDUCTORS (With Tracker Only) 7-1. Diodes The most basic type of solid state semiconductor component is the diode. Diodes are formed by creating a junction between p-type and n-type semiconductor material. The PN junction gives diodes and semiconductor components polarity characteristics that allow them to conduct current when an external voltage is applied.
  • Page 63 You can see this "knee" signature on some diodes in the next section. Do the following to display the analog signature of a diode: 1. Select 50, 10V and 60Hz. 2. Place or clip the red test lead from the Access Tracker's Channel A jack to anode lead of the diode.
  • Page 64: Affects Of Frequency (F S ) On Diode Signatures

    Affects of Frequency (F ) on Diode Signatures With the 3V, 50 selected and the test signal frequency of 60 Hz, the signature of the diode is shown on the left figure below. Changing only the test signal frequency to 5 kHz displays the signature on the right.
  • Page 65: Composite Diode Signatures

    Composite Diode Signatures A composite analog signature is a combination of several components connected together in an electronic circuit. Up to this point, we have been showing you what the basic component signatures look like out of circuit. In the real world of electronics troubleshooting, components are connected together in a circuit and when testing with ASA, the signatures are a composite that may appear quite complex.
  • Page 66: Diode Failures

    Figure 7-9. Composite Model of a Diode and Resistor in Parallel. = 50  = 10 V, R = 10 V, R = 1K = 200 mV, R = 1K Figure 7-10. Composite Signature - 1N914 Diode and 1.5K Resistor in Parallel. The signature on the left shows only the diode signature because the test signal resistance is set below any visible contribution due the 1.5 k...
  • Page 67 54 10V 1K 15V 20K, 20V Figure 7-12. Defective Diode Signature with a 50  Series Resistor. The LOW range shows that there is a resistive component to the signature when the diode is conducting. This is the result of a defect in the diode's internal PN junction. The resistance is visible only in LOW range because the voltage drop across it is small.
  • Page 68: Internal Leakage In A Diode

    Internal Leakage in a Diode Figure 7-13. Defective Diode Model with an Internal Leakage Resistance. 50 10V 1K 15V 20K, 20V Figure 7-14. Signature of a 1N914Diode with Internal Leakage (10K in Parallel). Notice that in the 50 range, there does not seem to be a problem. In both medium ranges, you can see the diode conducting when it should be acting like an open.
  • Page 69 Figure 7-15. Access Tracker Core Circuit Block Diagram with a Zener Diode. Figure 7-16. Single Zener Diode and 2 Zener Diodes in Series. Single 1N5239B Zener Diode 2 Zener Diodes in Series, 1N5239B Figure 7-17. Signatures of Zener Diodes at 20V, 20K Since each horizontal division on the Signature graticule (in 20V range) is approximately 5 Volts, from the signature on the left you can estimate that this is about a 9 volt Zener diode.
  • Page 70: Review

    Review • Diodes conduct current in one direction (forward biased) and not the other. The diode's analog signature displays this characteristic as the “knee” effect or pattern. • Diodes have polarity, an anode and a cathode. • Diode defects, other than opens and shorts, are usually resistive. •...
  • Page 71: Transistors

    Transistors A bipolar transistor is a three layer device. There are two basic types. A PNP transistor has a layer of n-type silicon material sandwiched between two layers of p-type material. An NPN transistor has a layer of p-type silicon material sandwiched between two layers of n-type material.
  • Page 72: Bipolar Transistor Signatures

    1. Use 5 Volts or less for testing the base-emitter or collector-emitter. 2. If using 6 Volts or greater, then keep the duration of the test as short as possible. 3. Identify the base, emitter and collector pins of the device and then test the collector-base junction to determine whether it is an NPN or PNP.
  • Page 73 Diode 1N914 PNP 2N3906 NPN PN2222A Figure 7-20. Signatures of a Diode and Collector-Base of Transistors at 1K and 15V. Notice that the collector-base signature of a NPN transistor is identical to the signature of diode. The collector-base signature of a PNP transistor, which has opposite polarity from a NPN, looks similar to a diode with its polarity reversed.
  • Page 74: Identifying Unknown Transistors

    Identifying Unknown Transistors Sometimes, we need to identify unknown transistors. We may need to replace one in a circuit for which we do not have a schematic. The Access Tracker makes this a relatively simple procedure because each type of junction has a characteristic signature. This makes it possible to identify each of the terminals and the polarity of the transistor.
  • Page 75: Darlington Bipolar Transistor Signatures

    Figure 7-25. Signature of Pins 1 And 3 Of an Unknown Transistor. Darlington Bipolar Transistor Signatures The Darlington transistor is basically two transistors paired together in a special configuration. The emitter of the first transistor is connected to the base of the second transistor.
  • Page 76 B-E Junction* C-E Junction** C-B Junction* Figure 7-27. Signature of a Darlington Transistor, TIP112 NPN Type at 20V and 20K. Note that the B-E junction has a sloped leg bend in its signature caused by internal resistors R1 and R2. User’s Manual 21-1352 Rev P...
  • Page 77: Review

    Review • A PNP bipolar transistor consists of a layer of N-type silicon sandwiched between two layers of P-type silicon. • A NPN bipolar transistor consists of a layer of P-type silicon sandwiched between two layers of N-type silicon. • To test a transistor, the base-emitter (B-E), collector-base (C-B) and collector-emitter (C-E) junctions all need to be examined.
  • Page 78: Solid State Switching Components

    Solid State Switching Components Optical Switches There are two types of optical switches: phototransistors and opto-couplers. Phototransistors can be used in two modes depending on the application. It can be used as either a light activated transistor or as a light activated diode. In either mode, light is used to turn it on and allow current to flow.
  • Page 79: Scrs And Triacs

    The phototransistor's signature is similar to a diode's signature in reverse breakdown mode when not activated by light and as a short signature when activated by a bright external light. SCRs and TRIACs A SCR and TRIAC are semiconductor components that are used in switching applications. A SCR (silicon controlled rectifier) is used for DC switching circuits.
  • Page 80: Review

    6. Place the red test probe to the SCRs anode lead and the black test probe to the SCRs cathode lead. 7. Observe the SCRs anode-gate signature. Gate-Anode Gate-Cathode Anode-Cathode Figure 7-31. Signatures of A SCR - C106B Type at 20V and 20K. Review •...
  • Page 81: Section 8 Testing Integrated Circuits (With Tracker Only)

    SECTION 8 TESTING INTEGRATED CIRCUITS (With Tracker Only) Digital Integrated Circuits Digital integrated circuit (IC) chips are made from transistors on a common substrate. Their analog signatures are typically variations of the discrete diode and transistor signatures. Most logic ICs, contain multiple circuits in one chip. These chips can have pins from 14 to over 200, although quite often many pins share quite similar signatures.
  • Page 82: Digital Integrated Circuit Signatures

    Digital Integrated Circuit Signatures Before we examine the analog signatures of an IC, let's study the block diagram of a 74LS245 octal bi-directional bus buffer to introduce some basic concepts. This IC is a member of the low power Schottky transistor-transistor logic family (LSTTL). Examine the block diagram for this chip below.
  • Page 83: Signatures Of Logic Ic Families

    4. Use the red test lead from the Access Tracker's Signal jack. Probe the enable input pins of the IC and view their signatures on the signature display. For this example, the enable pins of the 74LS245 are pin 1 and 19 and will have the same signatures. (Note: This is only for ICs out of circuit.) 5.
  • Page 84: Comparing Two Ttl Families

    Comparing Two TTL Families Although the logic function is the same, there are differences in the circuitry of each logic family. These differences can be readily seen in their signatures using the Access Tracker. We will illustrate these concepts with the following example of two hex inverters, a 7404 and a 74LS04 from different logic families.
  • Page 85: Cmos Logic Family

    without another reference chip available just compare each input's signature with the other five inputs. Similarly, compare each output's signature with the other five outputs. CMOS Logic Family CMOS circuits are constructed differently than TTL circuits. The inputs to CMOS transistors are capacitive due to the use of field-effect transistors (FET) instead of bipolar transistors used in TTL.
  • Page 86: Cmos Components And Test Frequency (F S )

    Figure 8-7. Signatures of A 74HC14 CMOS Hex Inverter. CMOS Components and Test Frequency (F CMOS logic circuits inherently have a significant amount of internal capacitance. This junction capacitance is visible in the CMOS signatures when using the Access Tracker. Capacitance in CMOS circuitry may be emphasized or de-emphasized by changing the frequency of the test signal.
  • Page 87: Review

    6. Move the red probe on pin 2, an output pin. Probe all the other output pins of the suspect component with the black probe until you have identified all the pins that have signatures that are the same as pin 2. Review •...
  • Page 88: Analog Circuits

    Analog Circuits Analog components and circuits represent another family of integrated circuit components and include operational amplifiers (op amps), comparators, references, regulators, timers and many other specialized functions. These components and circuits present more troubleshooting challenges that are unique to this particular family of ICs... Op Amps Frequently, each pin of an op amp creates a different signature on the Access Tracker.
  • Page 89: Troubleshooting Op Am Circuits

    Pin 2 -Input Pin 3 +Input Pin 6 Output Figure 8-10. Signatures of an Op Amp (741) at 10V, 50, 60Hz with Common to Pin 4. Pin 2 -Input Pin 3 +Input Pin 6 Output Figure 8-11. Signatures of an Op Amp (741) at 20V, 20K, 60Hz with Common to Pin 4. Troubleshooting Op Am Circuits Troubleshooting an op amp in-circuit may be very challenging.
  • Page 90: Linear Voltage Regulators

    Linear Voltage Regulators Voltage regulators are commonly found in many electronic assemblies. Some of the most popular integrated circuits of this type are three terminal devices like the 7805, a +5 volt DC regulator. The next figure shows the schematic and pin layout of the 7805 regulator. Different manufacturers implement their products with different topologies and manufacturing processes.
  • Page 91: Review

    Review • Integrated circuits are complex devices that are built using basic electronic components. • The IC signatures resemble Zener diodes. • There are many causes for IC failures and the Access Tracker can display its "health" as resistive leakage, an open or a short. •...
  • Page 92: Low Voltage Integrated Circuits

    Low Voltage Integrated Circuits There is a new family of logic that offers lower dynamic power consumption, lower operating voltages, higher output drive, faster AC speed, lower noise and better dynamic thresholds than HC CMOS. These features make this family attractive for low power applications such as battery operated portable applications (that is, laptop computers, pagers, phones, etc.).
  • Page 93: Review

    The ranges used above enhance the resistive fault signatures that are commonly found when troubleshooting this logic family. The test signal voltage V is lower than the TTL range groups to ensure that most descriptive signature is displayed. A higher V result is a signature going toward a short with would mask out flaws.
  • Page 94: Section 9 Testing Rf (Nfsa Models Only)

    For information about the NFSA Probe refer to the TEV NFSA Probe Manual. Software For information about building test and software features for the NFSA Probe refer to the TEV NFSA Probe Manual, NFSA Software Tutorial and the Huntron Workstation Help/Manual. Mounting a Board The PCB under test can be mounted into the Access2 Prober at one of four levels –...
  • Page 95: Section 10 Application Notes

    Z axis up/down travel. These boards have to be probed on the solder side. However, the component may be in the way when you try to clamp the board into the slot. The Huntron Access has an additional cutout in the base plate. This allows for additional clearance for the large components.
  • Page 96 User’s Manual 21-1352 Rev P...

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